Association Between Apical Periodontitis and TNF-α -308 G>A Gene Polymorphism: A Systematic Review and Meta-Analysis.

Currently, investigations have focused on the identification of Single Nucleotide Polymorphisms (SNP) involved in host response and its ability to generate an immunity deficiency. The aim of this study was to perform a systematic review (SR) and meta-analysis to evaluate the association between TNF-α -308 G>A polymorphism and apical periodontitis (AP) phenotypes. A broad search for studies was conducted. The following databases were used: PubMed, Scopus, Web of Science, and VHL (Medline, SciELO, Ibecs, and Lilacs). The MeSH terms "Periapical Periodontitis," "Periapical Abscess," "Polymorphism, Genetic," and "Polymorphism, Single Nucleotide" were used. MeSH synonyms, related terms, and free terms were included. Clinical investigations of individuals with different AP phenotypes in permanent teeth were selected. After application of the eligibility criteria, selected studies were qualified by assessing their methodological quality. A fixed effect model was used for the meta-analysis. The initial search identified 71 references. After excluding duplicate abstracts, 33 were selected. From these, two were eligible for quality assessment and were classified as being of moderate evidence. The included studies did not demonstrate association between AP and TNF-α -308 G>A SNP. However, the meta-analysis demonstrated an association between the genotype distribution and AP phenotype (OR= 0.49; confidence interval= 0.25, 0.96; p=0.04). The role of TNF-α -308 G>A SNP in AP phenotypes is debatable. Further studies are needed to confirm and understand the underlying mechanisms of the identified association.